There are two ways through which we can set tooltip on control. First one is via Class and second one is via Property.

Via Class:-

private void btnTooTrip_MouseHover(object sender, EventArgs e)
        {
            ToolTip ttp = new ToolTip();
            ttp.SetToolTip(btnTooTrip, "Click me to execute.");
           
        }

Via Properties:-

Step1:-Take one button on windows form and drag-drop tooltip control on form

Step2:-Write popup message on button’s properties “ToolTip on ToolTip1”